Ask Phoebe: Where does the motorway go at night? The ring road has the answer

Can you shed any light please on what's happening on the Northwestern Motorway? I drove home to the North Shore from Te Atatu late one night some weeks ago, and struck the detour. I ended up wending my way through the backblocks of the nearby suburbs, and still have no idea where I went. I feel sorry for the local residents who have all the motorway traffic going past their doors. I've had to do it again recently so was a little more practised - but where did the motorway go? I did notice a wee sign with an 0800 number on it but I wasn't quick enough to note it down. John Hansen, North Shore.

The detour and night-time closures are part of the Hobsonville Deviation project, which will connect the Northwestern Motorway (SH16) with SH18 (Hobsonville Rd) that now ends at the Greenhithe Bridge. It's all part of the Western Ring Route, an alternative route around Auckland. The detour is necessary because of a bridge being built at Westgate at the end of the Northwestern. When it's finished, it will be part of the interchange linking the two motorways.

The work is being done at night to try to minimise disruption to the motorway traffic. The uneven surface of a section of the Northwestern is being replaced at the same time. The phone number for more information is (0800) 520-202, and you can also check out www.nzta.govt.nz/upperharbourmotorway

And, the part you have been waiting for - the detour details.

Westbound traffic on the Northwestern takes the Royal Rd offramp. Turn right on to Makora Rd and then left on to Royal Rd. At the end of Royal Rd turn right on to Don Buck Rd, to end up at the Don Buck/Hobsonville Rd roundabout. You can then take SH16 to Kumeu or head back towards the Westgate shopping centre.

To get to Hobsonville or Greenhithe, turn right on to Royal Rd from Makora, cross over the motorway, turn left on to Moire Rd and then left again on to Oriel Ave. This will bring you out on to SH18.

For traffic heading west on SH18, the road is usually closed at Oriel Ave. Traffic is sent left down Oriel Ave and right to Moire Rd. At the end of Moire Rd, turn right to Royal Rd and then either turn left to head citybound at the Royal Rd onramp, or continue straight on Royal Rd and tie into the detour route described above to the Don Buck Rd/Hobsonville Rd roundabout. If SH18 is closed at Fitzherbert Ave, traffic is detoured to Fitzherbert Ave and left to Oriel Ave and follows the normal detour.

Eastbound traffic on SH16 diverts down Fernhill Drive, and right at Westgate Drive. At the end of Westgate Drive, turn left to Don Buck Rd, and left at Royal Rd. Follow Royal Rd and then choose the onramp for the Northwestern citybound, or continue straight and turn left at Moire Rd and left again at Oriel Ave for SH18.

The detours are, or should be, marked with red signs, but it's possible that some have fallen over or been removed.

It's confusing, but a check of the street map shows that the detours work. Good luck.

* An update on Gaunt St, and the origin of the name. Two kind readers have emailed to say that the street is named after Admiral Sir Ernest Frederick Augustus Gaunt, KBE, who served in the British forces at the Battle of Jutland (1916, during World War I), and was an aide de camp to King George V. He retired in 1925 and was knighted. His brother Guy was also an admiral in the Royal Navy.

More information on the street names in the Wynyard Quarter can be found at www.seacity.co.nz